The document discusses MPLS-based VPN connectivity among inter-provider ISPs, focusing on how VPNs utilize shared infrastructures for secure remote access across geographically separated sites. It outlines the architecture and processes involved, including the use of MPLS for efficient data forwarding and the redistribution of VPN information between ISPs. Two methods for achieving cross-ISP VPN connectivity are proposed, namely back-to-back VRF and ASBR-to-ASBR approaches, highlighting their configurations and functionalities.

1. MPLS BASED VPN CONNECTIVITY
BETWEEN INTER PROVIDER ISP’S
BY,
S.PREM KUMAR
Email : prem081011@gmail.com

2. • VPN(VIRTUAL PRIVATE NETWORK)
• A VPN uses shared public telecom infrastructure
like internet to provide secure access to remote
offices.
• By implementing VPN we connect geographically
separated customer sites.
• Originally introduced point to point between
customer by packet switching.
• By using VPN, distinct regions customer connected
via ISP’s.
INTRODUCTION:

3. • VPN mainly depends on :-
 different geographical area.
 different service providers.
• For this, VPN information has to
mutually redistributed.
OBJECTIVE:

4. • Inter ISP’s. allow VPN information to
redistributed between adjacent MPLS.
• So client sites communicate with each
other across multiple ISP’s..

5. MPLS
• MPLS (MULTIPROTOCOL LABEL
SWITCHING)
• Data carrying technique for high
performance telecommunications
network.
• Based on shortest path LABELS
• Avoiding complex lookups in a routing
table.

6. DATA FORWARDING IN MPLS:
R4 TO R1

7. ARCHITECTURE BLOCKS
CONTROL PLANE
Layer 3 Protocol exchange and its related processes
examples: OSPF,BGP and Layer distribution protocols
DATA PLANE
Forwarding engine that forwards based on labels or destination IP addresses

8. MPLS ARCHITECTURE:
• CONTROL PLANE: IGP(OSPF),LDP
IGP: FIB(Forwarding information base) Routing
table.
LDP(Label distribution protocol):LIB(Label
information base)
• DATA PLANE: Performs functions relating to
forwarding data packets derived from control
plane.

9. IP ROUTING PROTOCOLS
(IGP,BGP)
IP ROUTING TABLE
LABEL INFORMATION BASE
(LIB)
IP FORWARDING TABLE-
FORWARDING
INFORMATION BASE
(FIB)
LABEL FORWARDING
INFORMATION BASE
(LFIB)
Incoming
IP packets
Outgoing IP
Packets
Incoming MPLS
packets
Outgoing
MPLS
packets
CONTROL PLANE
DATA PLANE

10. FORMAT OF MPLS:
• LABEL : 20 Bits (0 to19)
• COS : (Class of service)
 3 Bits (19 to 22)
 Classification of customer based on QoS.
LABEL COS BOS TTL

11. • BOS: (Bottom of stack)
1 Bit (22 to 23)….Multi label/One label
• TTL: Time to live ( 23 to 31)
Maximum count: 255 (2^8-1).
Incase of loop condition,the TTL will become
zero.
Maximum : 30 hops.

12. EXISTING MODEL:

13. PROPOSED MODEL:

14. ABR(AREA BORDER ROUTER):-
• ABR can simultaneously belong to two or
more areas, one of which must be the
backbone area.
• ABR is used to connect the backbone area and
non-backbone area.
• It could be a physical connection or a logical
connection between non-backbone area and
the backbone area.

15. ASBR:-
• AUTONOMUS SYSTEM BOUNDARY ROUTER.
• ASBR is a device to exchange routing
information with other AS.
• It may be a router in the region or ABR.
• If a single OSPF device imports external
routing information, it becomes an ASBR.

16. Method 1:BACK TO BACK VRF
• The border provider edge (PE) routers residing
in different autonomous systems function as
ASBRs.
• ASBRs are interconnected either via a single
link consisting of logical sub-interfaces or via
multiple physical links.
• VRFs are configured on the ASBRs to collect
VPN client routes.

17. • The single client VRF can run eBGP, RIPv2,
EIGRP, OSPF, or static routing to distribute the
VPN routes to its adjacent peer.
• eBGP : Offering better policy, scalability, and
security mechanisms

19. DLCI:-
• Data link connection identifier.
• Identify virtual circuits.
• Given by service provider.
• Local DLCI maps with remote IP address.

20. FRAME RELAY:
• Frame uses virtual interface instead of
physical interface.
• The biggest benefit of these virtual lines is
that we do not need equal physical interfaces
on router to connect them.
• We can connect multiple virtual lines with
single interface.

21. Method 2: ASBR TO ASBR
• In the second method, the ASBRs use MP-
eBGP to peer with each other to transport
VPN routes between autonomous systems.
• It alleviates the need to have per-VPN
configuration on the ASBRs as seen in the
back-to-back VRF method, and thus allows
VPN prefixes to be transported across multiple
providers.

23. • Created a scenario of 3 networks with each
configure (OSPF).
• Because internally OSPF should run inside the
network for transmission of the exterior gate
way protocol like e-BGP.
• BGP Share the information to other
autonomous system with the help of OSPF
only.

24. RESULTS:

25. SERVICE PROVIDER NETWORK:

26. NEED OF MPLS :
• CORE: Lakhs of entries.
• IP Lookup
• Packet are facing Latency(Delay) in the core
network.
• PE Router will look the IP routing table and
put the label and forward to core router.
• Core routers will check the L2.5 not L3.

27. MPLS TERMINOLOGY:
• Adding the label : PUSH operation
Router : Ingress router
• Remove the label: POP operation
Router : Egress router
• Remove and Add : SWAP operation (Core)
Router : Transit router/ LSR (Label switching
router
• CORE : Full mesh topology

28. VRF (VIRTUAL ROUTING AND
FORWARDING)
• VPN ADDRESS: 32 Bit IP Address + RD (64
Bit)=96 bit address (VPNv4)
• RD : Route Distinguisher ( unique for every
company given by ISP’s)
• Internally they create logical router AS:RN
eg: Autonomous system no. of BSNL :
9829:100 , 100 is for customer no.
• RT : Route target (64 bit ) which branches have
to communicate.

29. Back to Back VRF :

30. BACK TO BACK VRF :
• Service provider 1 uses the protocol BGP AS1
and service provider 2 uses protocol BGP AS2.
• Configuration of VRF is done on both ASBR
routers namely PE1-ASBR1-AS1 and PE2-
ASBR2-AS2
• Conventional routing is configured between
MPLS VPN sites to distribute IPv4 packet to its
peer.

31. RESULTS:

32. RESULTS:

33. ASBR to ASBR APPROACH:

34. ASBR TO ASBR APPROACH:
• By next hop-self-method
• ASBR1-AS1 Announces itself as next hop to
P1-AS1-RR
• Similarly ASBR2-AS2 announces itself as next
hop to P2-AS2-RR.
• New VPNv4 label has been generated
between two different AS of ASBR.
• eBGP were used between ASBR1-AS1 and
ASBR2-AS2 and assigns new VPNv4 label.

35. • ASBR2-AS2 receives the VPNv4 route on the
MP-eBGP session from ASBR1-AS1.
• The next hop is modified from ASBR1-AS1 to
ASBR2-AS2.
• When ASBR2-AS2 propagates these routes via
the MP-iBGP session to P1-AS2-RR the VPN
label also get modified.
• The LSP path between the PE2-AS2 to ASBR2-
AS2 were used which has modified VPN label.

36. RESULTS:

37. RESULTS:

38. THANK YOU